The present invention relates to modified ink particles used for a colour liquid crystal display for a colour television, personal computer, or other apparatuses and a manufacturing method thereof, a colour filter incorporating the modified ink particles and a manufacturing method thereof, a colour display such as liquid crystal panels incorporating such a colour filter, and a manufacturing device of the modified ink particles.
In recent years, we have observed a growing demand for liquid crystal displays, especially, colour liquid crystal displays as a result of technological advances in the personal computer field, especially, in the portable personal computer field.
However, the liquid crystal display, especially, the colour liquid crystal display is still expensive, and a cutdown in the cost is unavoidable for a widespread use thereof. Particularly, a cutdown in the cost of colour filters to enable colour display is essential.
Conventional manufacturing methods of colour filters are approximately categorised into the following four methods.
The first method adopts a dyeing technique. According to the technique, a base material layer for dyeing is formed from water-soluble polymer materials on a glass substrate, and processed into a desired shape with a photolithographic technique, and the obtained base material layer is soaked in a dyeing agent to become dyed. The soaking operation is repeated thrice for the red (R), green (G), and blue (B) colours to form an RGB colour filter layer.
The second method adopts a pigment dispersion technique. According to the technique, a photosensitive resin layer in which a pigment is dispersed is formed, and processed into a desired pattern. The operation is repeated thrice for R, G, and B to form an RGB colour filter layer.
The third method adopts an electrodeposition technique. According to the technique, a translucent conductive film is formed on a substrate, processed into a desired pattern, and undergoes an electrodeposition in an electrodeposition coating liquid containing a pigment, a resin, and an electrolyte to form a monochromatic filter. The operation is repeated thrice for R, G, and B to form an RGB colour filter layer.
The fourth method adopts a printing technique. According to the technique, a thermosetting type resin in which a pigment is dispersed is printed. The operation is repeated thrice for R, G, and B to form an RGB colour filter layer.
These methods require the same operation to be repeated thrice to form a trichromatic RGB filter layer, adding to the cost. In addition, the printing technique does not produce a high resolution, and therefore is not suitable to form a pattern including highly fine pitches.
To make up the deficiencies, Japanese Laid-Open Patent Application No. 7-225308/1995 (Tokukaihei 7-225308) discloses a manufacturing method of a colour filter adopting an ink jet recording device (printer).
According to the manufacturing method, a curable resin layer containing methylol urea is formed on a substrate such as a glass substrate provided thereon with a lattice-like black matrix section. Subsequently, the resin layer corresponding to an empty space that is in a grid of the black matrix section is dyed by spraying solid inks of the respective RGB colours with an ink jet recording technique. The dyed resin layer is then caused to cure. Hence the method successfully forms a trichromatic RGB filter layer in a single operation, allowing a cut-down in the cost.
Nevertheless, the mutual wettability within the colour filter layer described in the aforementioned Patent Application is not satisfactory between the substrate and the resin layer and between the resin layer and the solid ink. Therefore, there occurs a problem of repelling between the layers, i.e., peeling of the layers at least at a segment of the interface therebetween, causing pin holes and other deficiencies in the colour filter layer.
In addition, regarding with the colour filter layer described in the aforementioned Patent Application, since the black matrix section is embedded in the colour filter layer, the height of the black matrix section is different from that of the colour filter layer, hampering the formation of a uniform surface on the black matrix section and the colour filter layer. Therefore, when such a colour filter is adopted in a colour display such as a liquid crystal panel, diffraction and refraction due to the non-uniform surface is likely to cause undesirable mixture of colour, and degrading colour display quality.
In addition, since the colour filter layer is formed by dispersing ink in a resin layer, the boundaries between the RGB colours are blurred. It is therefore necessary to provide a non-colouring section between adjoining RGB colouring sections to separate those colouring sections in the colour filter layer, which adds to skills and techniques required in the fabrication of the colour filter layer.
An object of the present invention is to offer modified ink particles that satisfy conventionally required properties in terms of heat resistance, solvent resistance, and resolution, as well as ink jet characteristics, that restrain occurrences of pin holes and other deficiencies, and that are readily fabricated into a colour filter; a manufacturing method thereof; a colour filter incorporating the modified ink particles; a colour display such as a liquid crystal panel using the colour filter; and a manufacturing device of the modified ink particles.
In order to achieve the object, a modified ink particle in accordance with the present invention, includes:
a main body; and
a modified portion formed from a modifier on at least a part of a surface of the main body by vapour-depositing the vapourised modifier on the surface of the main body that is floating.
In the modified ink particle as set forth above, when the main body is hydrophobic, the modified portion is preferably hydrophilic. Further, in the modified ink particle as set forth above, when the main body is hydrophilic, the modified portion is preferably hydrophobic.
With the aforementioned arrangement, it is possible to impart both hydrophobic and hydrophilic properties to the modified ink particle: for example, when the main body of the ink particle has hydrophobic properties, the modified portion thereof has hydrophilic properties; when the main body of the ink particle has hydrophilic properties, the modified portion thereof has hydrophobic properties.
For these reasons, with the aforementioned arrangement, when the modified ink particle is used in a colour filter layer or a black matrix layer which is formed, for example, on a substrate of a liquid crystal panel or on a resin layer formed on that substrate, regardless of whether the substrate or the resin layer on the substrate is hydrophilic or hydrophobic, the modified ink particle shows improved affinity with the substrate and the resin layer due to its dual properties. Moreover, the modified ink particle shows improved affinity with, for example, the individual RGB colour filter layers and the black matrix layer that are provided adjacent to each other in the colour filter layer.
Therefore, the aforementioned arrangement restrains occurrences of deficiencies of conventional technique: for example, poor mutual wettability, mutual repelling, peeling at least at a part of the interfaces, and a high likelihood of pin holes in the colour filter layer.
In order to achieve the object, a manufacturing method of a modified ink particle in accordance with the present invention, includes the steps of:
(a) floating a main body of an ink particle;
(b) mixing the floating main body of the ink particle with a vapourised modifier; and
(c) vapour-depositing the vapourised modifier on a surface of the main body of the ink particle to form a modified portion formed from the modifier on the surface of the main body of the ink particle.
With the method as set forth above, the vapourised modifier may be vapour-deposited by turning the vapourised modifier into an oversaturation state by means of adiabatic expansion. Moreover, with the method as set forth above, the vapourised modifier may be vapour-deposited by turning the vapourised modifier into an oversaturation state by means of cooling. Furthermore, with the method as set forth above, the vapourised modifier may be vapour-deposited by turning the vapourised modifier into an oversaturation state by means of mixing the vapourised modifier with the main body of the ink particle that is cooler than the vapourised modifier.
With these method, the vapourised modifier can be distributed in a substantially uniform manner around the main body of the ink particle. Therefore, if such vapourised modifier is vapour-deposited, for example, in an oversaturation state, the vapourised modifier can be uniformly vapour-deposited on the surface of the main body of the ink particle.
Therefore, with the method, since the surface of the fine main body of the ink particle can be modified with a modifier that can be more surely supplied to the surface, the modified portion can be formed only on the surface of a fine main body of the ink particle, the amount of the modifier used can be reduced, the formation of the modified portion can be stabilised.
As a result, with the method, it becomes possible to more surely manufacture a fine modified ink particle having a more uniform modified portion.
In order to achieve the object, a colour filter in accordance with the present invention has a water repellent resin layer on a plastic substrate and a colouring section formed from the modified ink particle on the water repellent resin layer. Another colour filter in accordance with the present invention has a hydrophilic resin layer on a glass substrate and a colouring section formed from the modified ink particle on the hydrophilic resin layer. The colouring section may be, for example, a colour filter layer or a black matrix layer.
With the arrangement as set forth above, it is possible to impart both hydrophobic and hydrophilic properties to the modified ink particle: for example, when the main body of the ink particle has hydrophobic properties, the modified portion thereof has hydrophilic properties; when the main body of the ink particle has hydrophilic properties, the modified portion thereof has hydrophobic properties. For these reasons, with the arrangement, when the modified ink particle is used in a colour filter layer or a black matrix layer which is formed, for example, on a substrate of a liquid crystal panel or on a resin layer formed on that substrate, regardless of whether the substrate or the resin layer on the substrate is hydrophilic or hydrophobic, the modified ink particle shows improved affinity with the substrate and the resin layer due to its dual properties. Moreover, the modified ink particle shows improved affinity with, for example, the individual RGB colour filter layers and the black matrix layer that are provided adjacent to each other in the colour filter layer in a similar manner.
Therefore, the aforementioned arrangement restrains occurrences of deficiencies of conventional technique: for example, poor mutual wettability, mutual repelling, peeling at least at a part of the interfaces, and a high likelihood of pin holes in the colour filter layer. Consequently, the colour filter in accordance with the present invention shows an improved yield.
In order to achieve the object, a manufacturing method of a colour filter in accordance with the present invention is a manufacturing method of the aforementioned colour filter, and includes the step of forming the colouring section of the modified ink particle with an ink jet technique using the modified ink particle.
With the method as set forth above, the modification allows, for example, the colour filter layers each having a colouring section of one of the three colours to be concurrently formed from a plurality of modified ink particles, for example, on a substrate or on a resin layer on that substrate, using an ink jet technique for the modified ink particles, so that the colour filter layers, as well as the black matrix layer, form a common flush surface. Therefore, with this method, the manufacturing process of the colour filter is less complex and produces a colour filter having better optical properties than conventional techniques.
In other words, with the method as set forth above, it is possible to modify hydrophobic carbon black by oxidisation using, for example, nitric acid, and to use, as a modified ink particle for a black matrix, the carbon black having a modified surface to which hydrophilic properties developing from, for example, a carboxyl group formed by oxidisation are imparted. Moreover, with the method, a hydrophilic colour particle for use with the colour filter can be modified with paraffin or other hydrophobic substances, and modified colour particles to which hydrophobic properties are imparted can also be used as RGB modified ink particles.
Hence, the surface of the individual modified ink particle is modified and have better physical properties. Therefore, even if the ink particles are adjacent to each other or to a resin layer provided on the substrate, i.e., the occurrences of pin holes and other deficiencies, is restrained based on repelling resulting from poor mutual wettability, it becomes possible to form the modified ink particles adjacent to each other.
Hence, even if the colouring sections of colour filters, such as the black colouring section of a black matrix layer and the RGB colouring sections, are concurrently formed from the modified ink particles radjacent to each other, using an ink jet technique for the modified ink particles, so that the colouring sections form a common flush surface, occurrences of pin holes and other deficiencies, which were highly likely to occur with conventional techniques in the interface, are restrained. Moreover, with this method, since the colouring sections can be concurrently formed to form a common flush surface, light diffraction and refraction can be reduced with the obtained colour filter due to the common flush surface. Consequently, with the method, a colour filter with restrained occurrences of deficiencies and diffraction and greatly improved optical properties becomes readily available in a stable manner.
In order to achieve the object, a colour display device in accordance with the present invention includes the aforementioned colour filter. With the arrangement as set forth above, since the colour filter can be made to develop a less likelihood of pin holes and other deficiencies and to have colouring sections having a common flush surface, poor display due to light diffraction or refraction and other conventional deficiencies can be restrained and the yield is improved, which in turn improves the quality in colour display, and makes it possible to cut costs.
In order to achieve the object, a manufacturing device of a modified ink particle in accordance with the present invention includes:
a modification operating section having inside thereof a sealable processing space;
a particle introduction port for introducing a main body of an ink particle into the processing space;
a particle exhaust outlet for removing a modified ink particle of which at least a surface is modified by a modifier from the processing space; and
control means for mixing the main body of the ink particle that has been introduced through the particle introduction port and that is floating with the vapourised modifier in the processing space, turning the vapourised modifier into an oversaturation state by means of temperature control or pressure control of the processing space, vapour-depositing the vapourised modifier on a surface of the main body of the ink particle, forming a modified portion formed from the modifier on the surface of the main body of the ink particle, and removing the modified ink particle through the particle exhaust outlet.
With the arrangement as set forth above, the provision of the control means enables the aforementioned modified ink particles having good properties to be obtained in a stable manner.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realised and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.